An internal combustion engine described in Patent Document 1, for example, includes a ratchet type one-way clutch, which is arranged between the output shaft of an engine starting motor (hereinafter, a starting motor) and a crankshaft. The clutch has a pocket portion formed in the inner circumferential surface of an outer race member, which is connected to the crankshaft. A claw piece is supported by a corner portion of the pocket portion in a radially inclinable manner. An engagement portion, with which the claw piece is engaged, is formed in an inner race member connected to the output shaft of the starting motor. A spring constantly urges the claw piece radially inward, or, in other words, in a direction in which the claw piece becomes engaged with the engagement portion. When the engine speed exceeds a rotational crank speed of the starting motor, or when engine starting is completed, the clutch suspends torque transmission from a ring gear to the crankshaft and from the crankshaft to the ring gear.